Tension control apparatus



March 5, 1963 D. E. FISHER ETAL TENSION CONTROL APPARATUS Filed Aug. 5, 1961 mmvroxs. FlSHER v DON E By DOUGLAS J. LAMB 1M3 7n. Tm

ATTORNEY 3,08%,132 TENSEON CGNTRQL APPARATUS Don E. Fisher, Pensacola, and Douglas J. Lamb, Gulf Breeze, Fla, assiguors, by mesne assignments, to Monsanto Chemical (Iompany, a corporation of Delaware Filed Aug. 3, 1961, Ser. No. 129,119 3 Claims. (Cl. 242-15 9 This invention relates to tension control apparatus for effecting a uniform constant tension in yarn being forwarded to winding devices, knitting machines, or the like. More particularly, this invention relates to an improved self-operable tensioning device of the type adapted to compensate for fluctuations in tension in a moving yarn so as to establish a constant uniform delivery tension therein with a minimum of yarn contact, interference, and displacement.

In many textile operations, it is important that y-arn be delivered to machines at a constant tension to prevent production of irregular and substandard products. Various types of tensioning devices or tensioners have been suggested. Two of the more common constructions include the gate-type tensioner, in which yarn passes between intermeshing posts or fingers, and the disctype tensioner, in which yarn passes between a pair of discs, one of which is usually spring biased.

The suggested tensioning devices presently in use possess disadvantages. Many devices are not designed to provide a uniform constant tension while others do not meet the necessary degree of accuracy, sensitivity and responsiveness demanded. Some designs are complicated in structure and expensive to manufacture, while oscillation and vibration difficulties are encountered with the employment of other modifications.

It is an object of this invention to provide constant tension control apparatus possessing features of simplicity, compactness, responsiveness, and economy. Another object is to provide an improved tensioner adapted to delicately sense variations in stress in a moving yarn and to act responsively to such variations so as to augment or to reduce drag on the yarn for establishing a predetermined uniform tension therein. Another object is to provide a compensating tensioner that adjusts the amount of applied tension according to changes in tension in yarn forwarded to the tensioner so as to maintain a constant delivery tension therein. A further object is to provide constant tension control apparatus of the type requiring minimal yarn contact, interference, and displacement. A still further object is to provide a tensioner of the type utilizing pivotal means having a control arm to sense variations in tension in a moving yarn and to concurrently and automatically control actuation of wrapping means, associated with the pivotal means, for providing a constant uniform yarn delivery tension.

According to the invention, tension control apparatus of the above type designed to deliver yarn to a device at a constant uniform tension is provided. In general, the invention comprises rockable lever means pivotally fulcrumed about pivot means suitably fixed on a support member. The support member is adapted to be bolted to a base and is interposed in the path of a moving yarn traveling from a source of yarn supply to a knitting or winding device. The yarn normally travels from the source of yarn supply to a guide on the support member and moves in a substantially downward direction engagiugly past stationary and movable friction means mounted on the rockable lever means and the support member, respectively. Preferably, the movable and stationary friction means comprise a plurality of pins arranged in preselected manner to effect different degrees of yarn wrap therearound as determined by the degree and direction of oscillation of the rockable lever means.

atent D f 3,80,l32 Patented Mar. 5, 1963 The rockable lever means is limited in its clockwise and counterclockwise notation about the pivot means by spaced stop means located on the support member. From the movable and stationary friction means, the yarn travels to an eyelet secured on one end of the rockable lever means for guiding the yarn to the knitting or winding device. A counterbalancing weight is slidably mounted on the other end of the rockable lever means to provide a turning moment to the latter.

In operation, the weight is adjusted at a preselected point on the rockable lever means to apply a desired moment force to act on the yarn. As the yarn moves through the tension control apparatus, the rockable lever means detects fluctuations in tension in the yarn forwarded thereto from the source of yarn supply, and swings in one direction or in the opposite direction for correspondingly adding tension to or subtracting tension from the yarn for maintaining a constant uniform tension in the yarn being delivered to the knitting or Winding device.

A further understanding of the advantages, organization, and operation of the invention will be gained by reference 'to the detailed description of the structure and operation of the invention and to the accompanying drawing, which is intended merely to be illustrative and not limitative.

In the drawing:

FIGURE 1 is a perspective view of the tension control apparatus embodying the invention shown interposed in the path of a yarn moving from a yarn supply source to a device;

FIGURE 2 is a partial view showing a modification of the invention.

Like components shown in the several figures in the drawing are designated by the same reference numerals for purposes of convenient identification.

Referring to FIG. -1 of the drawing, the tension control apparatus 1 embodying the invention is shown interposed in the path of a yarn 2 moving from a yarn supply package 3 to such as a knitting device 4, only a part of which is shown.

The apparatus 1 comprises an elongated lever 5 having a pair of oppositely extending moment arms, 6 and 7, a control arm and 1a counterbalaneing arm, respectively. Lever 5 is rockably fulcrumed, between arms 6 and 7, about a pivot pin 8 mounted on a support member or plate 9 having a vertical face 10. Pivot pin 8 extends outwardly and perpendicularly from vertical face 10, and lever 5 is spaced from face 11 of member 9 by a sleeve element 11 coaxially mounted about pivot pin 8 between lever '5 and face 10. Support member 9 is, preferably, provided with openings 12 to permit member 9 to be fixedly bolted to a base or framework.

An eyelet guide 13, for moving the yarn guidedly therethrough, is secured to the outer end of control arm 6 which is bent in a direction perpendicular to the longitudinal axis of arm 6 and extends outwardly from vertical face 10 of member 9. The axis of eyelet 13 is arranged to be parallel to the longitudinal axis of lever 5 and is spaced therefrom.

A mass or Weight 14 is slidably mounted on counterbalancing arm 7 of lever 5 and is provided with a setscrew to lock weight 14 in any desired position along the length of arm 7. The position of Weight 14 on arm 7 determines the moment force which will act on yarn 2 at the outer end of control arm 6.

Adjacent the fulcrum point of lever 5, there are a pair of spaced Wrapping pins, 15 and 16, each being fixedly secured at one end thereof on lever 5 at diametrically opposite sides of pivot pin 8 and each extending perpendicularly outwardly from lever member 5 and face 10 of member 9. Pins 15 and 16 are also arranged so that a line drawn through their axes is inclined to a vertical line passing through the axis of pivot pin 8. Yarn 2 normally moves engagingly past each pin, 15 and 16, in a winding path leading. from one side of pin 15 to the opposite side of pin 16, so that when the pins revolve about pivot pin 8, they will either increase or decrease the degree of wrap of the yarn therearound according to clockwise or counterclockwise movement of lever 5.

Rockable movement of lever 5 in a clockwise direction and oppositely in a counterclockwise direction about pivot pin ii is defined by an upper stop member 17 and a lower stop member 18, respectively, mounted on vertical face it? of plate 9. Stop members, 17 and 18, project surliciently outwardly from face ill of plate 9 to be within the oscillating path of lever 5 so as to engage control arm 5 and to arrest its clockwise and counterclockwise movement.

A pair of spaced stationary friction posts or pins, 19

and 2%), upper and lower, respectively, are each fixedly secured at one end thereof to support member 9 and extend perpendicularly outwardly from vertical face lit. losts 19 and 2d are primarily provided to lead the yarn into and to guide the yarn away from wrapping pins and 1h.

Preferably, upper post 19 is located directly above wrapping pin 15 and lower post it) is located directly below wrapping pin in when lever member 5 is in a horizontal position, as shown in the drawing, The yarn normally passes downwardly in a tortuous or serpentine path from stationary post i to wrapping pin 15, then moves to pin 16 and around pin Ell, engaging alternately opposite sides of the posts and pins in the successive order stated.

An annular guide 21 is positioned over and above pivot pin 8 such that the axis of the opening the guide is vertically disposed, as shown in the drawing, to permit the yarn passing therethrough to move substantially downwardly to wrapping pins 15 and 16. Guide 21 is secured to one end of an extension 22 which has s opposite end connected to support member 9 for supporting guide 21 in spaced relation from vertical face in of plate 9.

Prior to operation, the yarn 2 is laced in the following manner. The end of the yarn is led from supply package 3 through the opening in annular guide 21, and is then advanced downwardly and engagingly past the left side of stationary post 19, the right side of wrapping pin 15, the left side of wrapping pin 16 and the right side of stationary post 29, as shown in the drawing. From post 29 the yarn is advanced through eyelet 13 and forwarded substantially vertically downwardly to the knitting device d. 7

Weight 14 is now positioned, at a certain preselected point along the length of the counterbalancing arm 7, so that the lever 5 and therefore control arm 6 will, preferably, be biased in a generally horizontal position.

Operation is initiated when the knitting device is put into operation. In order to describe the conditions of operability, let it first be assumed that the conditions are normal, whereby lever 5 is balanced in a horizontal position and whereby the yarn is being forwarded to the knitting device 4 at a constant uniform tension of 3 grams. Further, let it be assumed that the take-off tension or the incoming tension, that is, the pull required to take the yarn all of the supply package 3, is 2.5 grams, and that the wrapping pins, 15 and 16, are adding 0.5 gram drag on the yarn to produce a total tension of 3 grams.

Now, if the take-off tension decreases to 2 grams, the control arm 6 will sense the reduced tension and since it will take 3 grams of tension on the yarn to maintain lever member 5 in a horizontal position, a rotational moment force will be effected such that lever 5 will swing in a clockwise direction. As lever 5 swings in a clockwise direction it carries the wrapping pins, 15 and 16, revolvingly around the pivot pin 8 correspondingly in a clockwise direction, thus increasing the wrap on the yarn and thereby adding tension thereto. When lever 5 has swung a certain degree and actuated the wrapping pins, 15 and 16, to a point where 0.5 gram of tension is added to the yarn to compensate for the 0.5 gram of reduction in takeoff tension, the lever 5 will once again be balanced, but in a position where the control arm 6 is nearer the upper stop member 1?. it will be noted that pins 15 and 16, in this base, will be applying a total of 1 gram of tension to the yarn since the pins were already applying 0.5 gram when the lever member 5 was in a horizontal position.

if the take-oil tension then increases 0.5 gram so that the take-off tension is once again 2.5 grams, control arm 6 will sense the increase in tension in the yarn and the leier 5 will be caused to swing in a counterclockwise direction because the force acting on the end of control arm 6 will be greater than 3 grams. As lever 5 swings in a counterclockwise direction, the wrapping pins, 15 and i6, revolve around pivot pin ll, also in a counterclockwise direction, to decrease the wrap of the yarn around pins 15 and is for reducing drag and tension in the yarn. When lever 5 has swung a certain degree so that the increase in drag has been compensated for by a corresponding reduction in tension, lever d wil then be balanced in a horizontal position.

Thus, lever 5 will continually adjust and compensate for increases and decreases in the takeoff tension to provide a constant uniform delivery tension in the yarn. it will be noted that control arm (9 will always move so as to adjust the applied tension, via the wrapping pins 15 and 16, so that the sum of the take-off tension, or incoming tension in the yarn, plus the applied tension always equals the constant predetermined uniform delivery tension.

FIG. 2 shows another embodiment of the apparatus 1. The modification comprises providing another wrapping pin 23 for applying a greater degree of wrap on the yarn after lever 5 .as rotated a predetermined degree in a clockwise direction. Pin 23 is s cured at the end of an upwardly projecting arm 24, preferably integrally formed with lever member 5' near the fulcrum point thereof, and is positioned on arm 24 so that the pin contacts the yarn above stationary post 19.

The positioning of the wrapping pins 15 and 16 and wrapping pin 23 in close adjacency to the fulcrum point of lever member 5, as shown in FIGS. 1 and 2, provides advantages in that the pins 15, 16, and 23 do not subject the yarn to any significant moment forces, but act merely to apply or reduce wrap on the yarn.

The tension control apparatus embodying the invention, as described above, provides features of simplicity and economy as well as accurate and responsive constant tension control in a moving yarn.

It is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. Tension control apparatus for controlling tension in a yarn moving from a source of yarn supply to a device, said apparatus comprising support means, pivot means on said support means, rockable lever means fulcrumed about said pivot means and having an elongated end, guide means on said elongated end for guiding the yarn to the device and adjustable weight means mounted on the other end of said rockable lever means for counterbalancing the latter, a plurality of spaced movable pins mounted on said rockable lever means and located about the fulcrum point of said rockable lever means, a plurality of spaced stationary pins located on said support means adjacent said spaced movable pins, said spaced movable and stationary pins normally having engagement with the yarn and being arranged on different circles generated around the fulcrum point of said rockable lever means, two of said plurality of spaced movable pins being located in a circle generated nearest the fulcrum point of said rockable lever means and each of the two pins being arranged substantially equidistant and at substantially opposite sides of the fulcrum point, the yarn normally moving directly from one side of one to the other side of the other of said two spaced movable pins free of surface frictional contact therebetween, whereby upon downward movement of said guide means said plurality of spaced movable pins are simultaneously rotated in one direction thereby decreasing the length of yarn contact therewith and upon upward movement of said guide means said plurality of spaced movable pins are simultaneously rotated in the opposite direction thereby increasing the length of yarn contact therewith.

2, Tension control apparatus for controlling tension in a yarn moving from a source of yarn supply to a evice, said apparatus comprising a support member, a pivot pin carried on said support member, a rockable lever fulcrumed about said pivot pin and providing a pair of oppositely extending arms, an adjustable weight mounted on one of said arms of said rockable lever for counter-balancing and applying a turning moment thereto, an eye carried on the other of said arms for guiding said yarn to said device, a pair of spaced movable pins each secured on said rockable lever and each positioned substantially equidistant from and at substantially opposite sides of the fulcrum point thereof while being located on one circle generated around the fulcrum point of said rockable lever, a pair of spaced stationary pins each secured on said support member and each being positioned at substantially opposite sides and outwardly of said pair of spaced movable pins while being located on a second circle generated around said one circle, a guide member carried on said support member and positioned in overhanging relation over said pairs of spaced movable and stationary pins, said yarn normally moving from said guide member to one of said spaced stationary pins, to one of said pair of spaced movable pins and directly therefrom to the other spaced movable pin free of surface frictional contact therebetween, to said other spaced sta tionary pin, and then to said eye while alternately engaging opposite sides of each of said spaced movable and stationary pins, whereby upon downward movement of said eye said pair of spaced movable pins are simultaneously rotated in one direction thereby decreasing the length of yarn contact therewith and upon upward movement of said eye said pair of spaced movable pins are simultaneously rotated in the opposite direction thereby increasing the length of yarn contact therewith.

3. Tension control apparatus as claimed in claim 2, further characterized in that a third spaced movable pin is secured on said rockable lever and is located on a third circle generated around said second circle so as to be movable into engagement with said yarn between said guide member and said one of said pair of stationary pins for rapidly increasing tension in or substracting tension from said yarn.

References Cited in the file of this patent UNITED STATES PATENTS 828,203 Foster Aug. 7, 1906 1,375,568 Cunifi Apr. 19, 1921 2,964,259 Peel Dec. 13, 1960 FOREIGN PATENTS 22,908 Switzerland Nov. 16, 1900 

1. TENSION CONTROL APPARATUS FOR CONTROLLING TENSION IN A YARN MOVING FROM A SOURCE OF YARN SUPPLY TO A DEVICE, SAID APPARATUS COMPRISING SUPPORT MEANS, PIVOT MEANS ON SAID SUPPORT MEANS, ROCKABLE LEVER MEANS FULCRUMED ABOUT SAID PIVOT MEANS AND HAVING AN ELONGATED END, GUIDE MEANS ON SAID ELONGATED END FOR GUIDING THE YARN TO THE DEVICE AND ADJUSTABLE WEIGHT MEANS MOUNTED ON THE OTHER END OF SAID ROCKABLE LEVER MEANS FOR COUNTERBALANCING THE LATTER, A PLURALITY OF SPACED MOVABLE PINS MOUNTED ON SAID ROCKABLE LEVER MEANS AND LOCATED ABOUT THE FULCRUM POINT OF SAID ROCKABLE LEVER MEANS, A PLURALITY OF SPACED STATIONARY PINS LOCATED ON SAID SUPPORT MEANS ADJACENT SAID SPACED MOVABLE PINS, SAID SPACED MOVABLE AND STATIONARY PINS NORMALLY HAVING ENGAGEMENT WITH THE YARN AND BEING ARRANGED ON DIFFERENT CIRCLES GENERATED AROUND THE FULCRUM POINT OF SAID ROCKABLE LEVER MEANS, TWO OF SAID PLURALITY OF SPACED MOVABLE PINS BEING LOCATED IN A CIRCLE GENERATED NEAREST THE FULCRUM POINT OF SAID ROCKABLE LEVER MEANS AND EACH OF THE TWO PINS BEING ARRANGED SUBSTANTIALLY EQUIDISTANT AND AT SUBSTANTIALLY OPPOSITE SIDES OF THE FULCRUM POINT, THE YARN NORMALLY MOVING DIRECTLY FROM ONE SIDE OF ONE TO THE OTHER SIDE OF THE OTHER OF SAID TWO SPACED MOVABLE PINS FREE OF SURFACE FRICTIONAL CONTACT THEREBETWEEN, WHEREBY UPON DOWNWARD MOVEMENT OF SAID GUIDE MEANS SAID PLURALITY OF SPACED MOVABLE PINS ARE SIMULTANEOUSLY ROTATED 